A vehicle physical quantity estimating device including: a longitudinal vehicle body velocity estimating unit, estimating a longitudinal vehicle body velocity based on vehicle wheel velocities of each wheel; a longitudinal/lateral acceleration state value deviation computing unit, computing deviations in longitudinal and lateral acceleration state values based on output sensor signals corresponding to detected values of the vehicle motions of triaxial accelerations and triaxial angular velocities output from a sensor, and the estimated longitudinal vehicle body velocity; a low pass filter, letting only signals corresponding to motions that need attention pass through from the longitudinal/lateral acceleration state value deviation computing unit 14; and an attitude angle estimating unit, estimating the attitude angle based on the sensor signal(s), and signal(s) representing the deviations in longitudinal and lateral acceleration state values after low pass filter processing. Also, a memory medium, storing a computer program for the device.